Cometary - meaning and definition. What is Cometary
Online Dictionary

What (who) is Cometary - definition

Comets; Cometary; Dirty snowball model; Dirty snowball hypothesis; Dirty snowball theory; Black comets; Short-period comet; COMET; Short period comets; Long period comet; Commet; Long-period comet; Jupiter family comet; A1 comet; Comet Tails; Cometary nuclei; Disconnection event; Jupiter-family comet; Jupiter family; Halley-type comet; Encke-type comet; Jupiter family comets
  • A comet was mentioned in the ''[[Anglo-Saxon Chronicle]]'' that allegedly made an appearance in 729 AD.
  • [[Halley's Comet]] appeared in 1066, prior to the [[Battle of Hastings]], and is depicted in the [[Bayeux Tapestry]].
  • Nucleus of [[103P/Hartley]] as imaged during a spacecraft flyby. The nucleus is about 2 km in length.
  • eccentricity]] of its orbit and its rapid motion when close to the Sun.
  • dust trail]], the dust tail, and the ion gas tail formed by [[solar wind]].
  • Diagram showing the physical characteristics of a comet:<br/>a)&nbsp;Nucleus, b)&nbsp;Coma, c)&nbsp;Gas/ion tail d)&nbsp;Dust tail, e)&nbsp;Hydrogen envelope, f)&nbsp;Orbital velocity direction, g)&nbsp;Direction to the Sun.
  • Comet Borrelly]] exhibits jets, but has no surface ice.
  • Comet [[81P/Wild]] exhibits jets on light side and dark side, stark relief, and is dry.
  • Typical direction of tails during a comet's orbit near the Sun
  • [[Euler diagram]] showing the types of bodies in the Solar System
  • [[Halley's Comet]] in 1910
  • Gas and snow jets of [[103P/Hartley]]
  • access-date=20 November 2013}}</ref>
  • The [[Oort cloud]] thought to surround the Solar System
  • Principia]]''
  • C/2006 W3 (Chistensen) emitting carbon gas (IR image)
  • Perseid meteors]]
  • Page from a treatise by [[Tycho Brahe]] depicting his [[geocentric]] view of the [[Great Comet of 1577]]
  • Woodcut of the [[Great Comet of 1577]]

·adj Pertaining to, or resembling, a comet.
Coma (cometary)         
Comae; Coma (cometary)
The coma is the nebulous envelope around the nucleus of a comet, formed when the comet passes close to the Sun on its highly elliptical orbit; as the comet warms, parts of it sublimate. This gives a comet a "fuzzy" appearance when viewed in telescopes and distinguishes it from stars.
Cometary knot         
Cometary knots, also referred as globules, are structures observed in several nearby planetary nebulae (PNe), including the Helix Nebula (NGC 7293), the Ring Nebula (NGC 6720), the Dumbbell Nebula (NGC 6853), the Eskimo Nebula (NGC 2392), and the Retina Nebula (IC 4406). They are believed to be a common feature of the evolution of planetary nebulae, but can only be resolved in the nearest examples.



A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can subtend an arc of up to 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures and religions.

Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, which lie beyond the orbit of Neptune. Long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun by gravitational perturbations from passing stars and the galactic tide. Hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition.

Extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System. However, the discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. In the early 21st century, the discovery of some minor bodies with long-period comet orbits, but characteristics of inner solar system asteroids, were called Manx comets. They are still classified as comets, such as C/2014 S3 (PANSTARRS). Twenty-seven Manx comets were found from 2013 to 2017.

As of November 2021 there are 4,584 known comets. However, this represents a very small fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System (in the Oort cloud) is about one trillion. Roughly one comet per year is visible to the naked eye, though many of those are faint and unspectacular. Particularly bright examples are called "great comets". Comets have been visited by uncrewed probes such as the European Space Agency's Rosetta, which became the first to land a robotic spacecraft on a comet, and NASA's Deep Impact, which blasted a crater on Comet Tempel 1 to study its interior.

Pronunciation examples for Cometary
1. That's cometary panspermia.
Searching for Life in the Solar System _ Alfonso Davila _ Talks at Google
2. of more local panspermia-- cometary panspermia,
Searching for Life in the Solar System _ Alfonso Davila _ Talks at Google
3. polled all the cometary scientists before,
Automated Science Operation Scheduling _ Steve Chien _ Talks at Google
4. through that cometary tail, and it's
A Planet for Goldilocks _ Natalie Batalha _ Talks at Google
5. So they're almost-- they're not cometary-like.
Natalie Starkey _ Talks at Google
Examples of use of Cometary
1. The Stardust spacecraft, meanwhile, may someday see further cometary action.
2. And other flyby missions have allowed scientists to draw some crude conclusions about cometary dust.
3. Mission scientists are filling in important new portions of a cometary picture that is still far from finished.
4. Dust from a comet‘s nucleus reflects sunlight and generates the cometary tail.
5. Andrew Coates, of the Mullard Space Science Laboratory, said÷ It is a fantastic day for cometary exploration.